<!DOCTYPE html>
<html>
  <head>
    <script>
      function doTest() {
        document.getElementById("t").style.display = "table-row";
      }
    </script>
  </head>
  <body onload="doTest()">
    <table style="border-collapse: collapse">
      <tr style="display: block; border: 5px solid">
        <td>LongLongLong</td>
      </tr>
      <tr style="display: none; border: 5px solid" id="t">
        <td>Short</td>
      </tr>
    </table>
  </body>
</html>
